An interview with Florenci Serras

Florenci Serras

As a PhD student at the University of Utrecht, The Netherlands, I studied development and evolution with my supervisor Jo.A.M. van den Biggelaar. Later as a postdoc with Scott E. Fraser at the UC Irvine, USA, I used live imaging to understand how in vivo cells communicate in the skin using the chick embryo as a model.  Both scientists transmitted to me the enthusiasm for exploring how cells talk to each other through development. In 1993, I went back to Spain and thanks to the influence of the inspiring work of Antonio García Bellido, I decided to apply my knowledge to developmental genetics in Drosophila. Working closely with García Bellido I learned Drosophila genetics and the use of genetic mosaics and screens. My colleague Montserrat Corominas and I decided to join forces and start a research group on Drosophila developmental genetics at the University of Barcelona. Today my lab is completely devoted to the understanding of the early signals and genomic responses that follow tissue damage in Drosophila regeneration. 

What are the advantages and disadvantages of working with Drosophila as a model system? 

The most obvious advantage of Drosophila is its use in genetic studies. The short life span and the large production of offspring, have made this organism a valuable animal model for genetic analysis.  

The 15500 genes packed in only four pairs of chromosomes, together with a fully sequenced and annotated genome, have been key in making this model organism perfect for exploring the regulation of gene expression in development. These features make Drosophila a very manageable model. As a consequence, a wide variety of sophisticated genetically engineered tools have been developed and are available to the entire scientific community through different platforms and universities. Moreover, many genes responsible for human diseases have orthologous counterparts and show functional similarities in flies.  

Another advantage is the reduced number of paralogous genes, as an indication of low redundancy, which has been crucial for understanding gene function. This has been pivotal for designing genetic screens to identify members of particular signaling pathways and cellular processes and for assigning basic functions to complex gene families. 

In addition, the availability of balancer chromosomes that allow the maintenance of mutations in the absence of recombination and their detection by a variety of genetic markers has been unique in making rapid progress in research in Drosophila. 

Drosophila is also an excellent organism to teach genetics and development in the classroom, from high school students to the labs at our universities.  

In conclusion, I have been fascinated by the extensive knowledge on this organism that has been gathered over the last one hundred years.  

One potential disadvantage of the Drosophila model is that the central nervous system and the adaptative immune system differ substantially from vertebrates. However, the use of flies for genome-wide genetic or drug screens searching for basic properties and molecules to understand complex behaviors (neural or adaptative, for example) can provide a vast amount of information for translational research. 

What could the SEBD do for you? 

The SEBD is doing a great job in providing information and organizing regular meetings on the topic. I suggest though that the SEBD could increase its visibility and intercede more in scientific policies, for example by increasing the outreach about scientific results and their implications for the general public and society at large. This should have an impact on the institutions involved in scientific policies.  

Developmental biology is a discipline that has been flourishing for many years. However, I perceive that nowadays it has become less visible. The SEDB could help to restore this last point, in particular by increasing interactions with other disciplines. One interesting possibility would be the organization of small monographic conferences with members of different societies and different fields sharing a common topic. This type of format would be beneficial to the SEBD and increase the visibility of developmental biology. 

 

3. What are the big open questions in the field? 

We know a lot about development, but much less about growth. How a particular organ reaches the proper size and shape and how it stops growing, are relevant issues in developmental biology to explore. I admire the work done in that direction in vertebrate limb development and in the fly imaginal disc. Both are considered the result of a variety of models implying signals, morphogens, physical forces, scaling, orientation, positional values, or reaction-diffusion activators and inhibitors. This is an exciting playground for potential new advances and discoveries relevant to regeneration and regenerative medicine. For example, we are now unraveling the mechanisms that respond to damage, and activate proliferation, but we still do not know how regeneration stops to prevent the generation of overgrowths. A genome-wide search for regulatory regions and the occupancy of transcription factors and inhibitory complexes will be key in the near future to understand the circuitry of gene regulatory networks that control growth, size, and regeneration.